Polymers

24 pages, 10960 KiB

Open AccessArticle

Bacterial Cellulose-Based Nanocomposites for Wound Healing Applications

by Alexandra-Ionela Dogaru, Ovidiu-Cristian Oprea, Gabriela-Olimpia Isopencu, Adela Banciu, Sorin-Ion Jinga and Cristina Busuioc

Polymers 2025, 17(9), 1225; https://doi.org/10.3390/polym17091225 (registering DOI) - 29 Apr 2025

Abstract

Bacterial cellulose (BC) is a polysaccharide produced by Gram-positive and Gram-negative bacteria with a strictly aerobic metabolism, having a huge number of significant applications in the biomedical field. This study investigates the development of bacterial cellulose (BC)-based composite systems that incorporate cerium dioxide [...] Read more.

Bacterial cellulose (BC) is a polysaccharide produced by Gram-positive and Gram-negative bacteria with a strictly aerobic metabolism, having a huge number of significant applications in the biomedical field. This study investigates the development of bacterial cellulose (BC)-based composite systems that incorporate cerium dioxide nanoparticles (CeO₂ NPs) used as antibacterial agents to enhance wound healing, particularly for burn treatments. The innovation of this study resides in the integration of CeO₂ NPs synthesized by using a precipitation method using both chemical and green reducing agents, ammonium hydroxide (NH₄OH) and turmeric extract (TE), in BC membranes composed of ultrathin nanofibers interwoven into a three-dimensional network appearing as a hydrogel mass. Characterization by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR) confirmed the effective deposition of this agent onto the BC matrix. Antibacterial activity tests against E. coli and B. subtilis indicated strong inhibition for the composites synthesized following these routes, particularly for the BC-CeO₂-TE-OH sample, processed by employing both precipitating agents. Cytotoxicity evaluations showed no inhibition of cell activity. Additionally, loading the composites with dexamethasone endowed them with analgesic release over 4 h, as observed through ultraviolet–visible spectroscopy (UV-Vis), while the FTIR spectra revealed a sustained drug presence post-release. These findings highlight BC-based films as promising candidates for advanced wound care and tissue engineering applications. Full article

(This article belongs to the Special Issue Synthesis, Design, Preparation and Processing of Functional Polymer Composites)

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12 pages, 904 KiB

Open AccessArticle

Bond Strength of Universal Adhesive/Resin Cement Combinations Relying on Touch-Cure Mechanisms

by Annamaria Forte, Eugenia Baena, Claudia Mazzitelli, Edoardo Mancuso, Diego D’Urso, Gerardo Pellegrino, Laura Ceballos, Lorenzo Breschi, Annalisa Mazzoni and Tatjana Maravic

Polymers 2025, 17(9), 1224; https://doi.org/10.3390/polym17091224 (registering DOI) - 29 Apr 2025

Abstract

New dual-curing resin cements are constantly launched into the market to improve the bond strength between dentine and indirect restorations when light irradiation is limited by the restoration material. The present study evaluated the microshear bond strength (μSBS) of two dual-cured resin cements, [...] Read more.

New dual-curing resin cements are constantly launched into the market to improve the bond strength between dentine and indirect restorations when light irradiation is limited by the restoration material. The present study evaluated the microshear bond strength (μSBS) of two dual-cured resin cements, Estecem II Plus (EP) and Variolink Esthetic DC (VAR), when resin composite or dentine substrates were conditioned with their corresponding universal adhesives, Tokuyama Universal Bond II (TUB) and Adhese Universal DC (ADH). The experimental groups (n = 20) were (1) TUB/EP light-cured, (2) TUB/EP self-cured, (3) ADH/VAR light-cured, and (4) ADH/VAR self-cured. A μSBS test was performed after 24 h (T0) or after thermocycling (TC), and failure modes were assessed. Data analysis was performed using three-way ANOVA and Tukey tests (p < 0.05). In composite, TUB/EP self-cured demonstrated the highest μSBS at T0 and TC. After TC, TUB/EP self-cured and ADH/VAR light-cured remained stable (p > 0.05). In dentine, TUB/EP light-cured was statistically superior to TUB/EP self-cured and ADH/VAR self-cured at T0. Thermocycling decreased the μSBS of light-curing groups. TUB/EP achieved optimal μSBS when the manufacturer’s instructions were followed and the adhesive was self-cured, irrespective of the bonding substrate. However, ADH/VAR was more dependent on the type of bonding substrate than on the curing mode of the resin cement. Full article

(This article belongs to the Section Polymer Applications)

19 pages, 1460 KiB

Open AccessArticle

Specificity of Thermal Destruction of Nonwoven Mixture Systems Based on Bast and Viscose Fibers

by Altynay S. Kalauova, Ekaterina E. Palchikova, Igor S. Makarov, Georgiy A. Shandryuk, Amangeldi I. Abilkhairov, Danagul Zh. Kalimanova, Meirbek Zh. Naukenov, Gulbarshin K. Shambilova, Egor M. Novikov, Junlong Song and Alexander G. Smyslov

Polymers 2025, 17(9), 1223; https://doi.org/10.3390/polym17091223 (registering DOI) - 29 Apr 2025

Abstract

The research investigates the thermal behavior of mixed systems based on natural and artificial cellulose fibers used as precursors for carbon nonwoven materials. Flax and hemp fibers were employed as natural components; they were first chemically treated to remove impurities and enriched with [...] Read more.

The research investigates the thermal behavior of mixed systems based on natural and artificial cellulose fibers used as precursors for carbon nonwoven materials. Flax and hemp fibers were employed as natural components; they were first chemically treated to remove impurities and enriched with alpha-cellulose. The structure, chemical composition, and mechanical properties of both natural and viscose fibers were studied. It was shown that fiber properties depend on the fiber production process history; natural fibers are characterized by a high content of impurities and exhibit high strength characteristics, whereas viscose fibers have greater deformation properties. The thermal behavior of blended compositions was investigated using TGA and DSC methods across a wide range of component ratios. Carbon yield values at 1000 °C were found to be lower for blended systems containing 10–40% by weight of bast fibers, with carbon yield increasing as the quantity of natural fibers increased. Thus, the composition of the cellulose composite affects carbon yield and thermal processes in the system. Using the Kissinger method, data were obtained on the value of the activation energy of thermal decomposition for various cellulose and composite systems. It was found that natural fiber systems have three-times higher activation energy than viscose fiber systems, indicating their greater thermal stability. Blends of natural and artificial fibers combine the benefits of both precursors, enabling the deliberate regulation of thermal behavior and carbon material yield. This approach opens up prospects for the creation of functional carbon materials used in various high-tech areas, including thermal insulation. Full article

(This article belongs to the Special Issue Natural Fiber-Based Green Materials, Second Edition)

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15 pages, 6035 KiB

Open AccessArticle

Improving Tribological Performance of Poly(phenylene sulfide) by Incorporating PTFE Fillers: The Influence of Filler Type and Concentrations

by Junpeng Li, Jixiang Li, Jianbo Xiang, Xiaoxi Gong, Peng Xie, Yang Chen, Mei Liang, Huawei Zou and Shengtai Zhou

Polymers 2025, 17(9), 1222; https://doi.org/10.3390/polym17091222 - 29 Apr 2025

Abstract

Poly(phenylene sulfide) (PPS) is a high-performance thermoplastic engineering material with excellent comprehensive performance that finds application in many fields due to its good processability, excellent heat resistance, and mechanical properties. However, the poor friction and wear properties of PPS limit its wide application [...] Read more.

Poly(phenylene sulfide) (PPS) is a high-performance thermoplastic engineering material with excellent comprehensive performance that finds application in many fields due to its good processability, excellent heat resistance, and mechanical properties. However, the poor friction and wear properties of PPS limit its wide application in industrial sectors. In this work, polytetrafluoroethylene (PTFE) was adopted as the solid tribo-modifier to improve the tribological performance of PPS. The efficacy of using three types of PTFE fillers, namely PTFE fiber, micropowder, and nanopowder, was comparatively investigated. The results revealed that the incorporation of PTFE was beneficial to improving the tribological properties of PPS and PTFE nanopowders, which were prepared by irradiation treatment technology that demonstrated the best modification effect in terms of both tribological and mechanical performance among the studied systems. In addition, the coefficient of friction and specific wear rate of PPS composites with 30 wt% nanopowders reached 0.165 and 3.59 × 10⁻⁵ mm³/Nm, respectively, which were 70.7% and 99.0% lower than their pure PPS counterparts. The above finding was attributed to the improved compatibility between the PTFE nanopowders and the PPS substrate as well as the easier formation of intact PTFE transfer film on the contact surface. This work shows some perspective for designing self-lubricating polymer composites that broaden their application in industrial sectors. Full article

(This article belongs to the Special Issue Mechanical and Structure–Property Relationships of Polymer Composites II)

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22 pages, 6724 KiB

Open AccessArticle

Exploring the Characteristics of Carbon Structures Obtained from LignoBoost Lignin

by Adina Coroabă, Irina Apostol, Ioan Andrei Dascălu, Adrian Bele, Narcisa Laura Marangoci, Florica Doroftei, Cristina Mariana Uritu and Iuliana Spiridon

Polymers 2025, 17(9), 1221; https://doi.org/10.3390/polym17091221 - 29 Apr 2025

Abstract

In the present study, carbon structures from LignoBoost lignin were synthetized using HNO₃/H₂SO₄ one-pot hydrothermal treatment, followed by a thermal treatment. The obtained compounds were characterized using different techniques, such as FTIR, DVS, DLS, XRD, fluorescence imaging and [...] Read more.

In the present study, carbon structures from LignoBoost lignin were synthetized using HNO₃/H₂SO₄ one-pot hydrothermal treatment, followed by a thermal treatment. The obtained compounds were characterized using different techniques, such as FTIR, DVS, DLS, XRD, fluorescence imaging and STEM. The formed LCMs presented graphitized structure with quasi-spherical shapes. All obtained materials presented negative values of zeta potential due to the charge from the hydroxyl and carboxyl groups, as confirmed by XPS analysis. All the data obtained sustained the heterogeneous composition of the lignin-based carbon materials, which arise from the complex structure of lignin. Fluorescence imaging demonstrated the potential of the materials as optical imaging agents. Full article

(This article belongs to the Section Biobased and Biodegradable Polymers)

20 pages, 7168 KiB

Open AccessArticle

Cellulose Extraction from Soybean Hulls and Hemp Waste by Alkaline and Acidic Treatments: An In-Depth Investigation on the Effects of the Chemical Treatments on Biomass

by Antonella Moramarco, Edoardo Ricca, Elisa Acciardo, Enzo Laurenti and Pierangiola Bracco

Polymers 2025, 17(9), 1220; https://doi.org/10.3390/polym17091220 - 29 Apr 2025

Abstract

The agri-food supply chain and other industries that convert agricultural raw materials into various consumer goods generate large quantities of by-products, most of which end up in landfills. This waste, rich in cellulose, provides a significant opportunity for the conversion of agricultural residues [...] Read more.

The agri-food supply chain and other industries that convert agricultural raw materials into various consumer goods generate large quantities of by-products, most of which end up in landfills. This waste, rich in cellulose, provides a significant opportunity for the conversion of agricultural residues into valuable products. In this paper, soybean hulls and hemp waste were subjected to chemical treatments with alkaline (NaOH 2% w/v) and acidic solutions (HCl 1 M) to remove non-cellulosic components and isolate cellulose. The biomass was characterized after each chemical process through FTIR, SEM, EDX, elemental analysis, TGA, and XRD. Lignin was determined following two different procedures, a conventional TAPPI protocol and a method recently proposed in the literature (CASA method). The results indicated that the chemical treatments favored the removal of organic compounds and minerals, increasing the cellulose content in biomass after each step. The purified product of soybean hulls consists of fibers 35–50 µm long and 5–11 µm thick, containing nearly pure cellulose arranged in crystalline domains. Fibers of variable sizes, rich in crystalline cellulose, were isolated from hemp waste. These fibers have diameters ranging between 2 and 60 µm and lengths from 40 to 800 µm and contain considerable amounts of lignin (~14%). Full article

(This article belongs to the Section Biobased and Biodegradable Polymers)

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11 pages, 1403 KiB

Open AccessArticle

Novel High-Efficiency Single-Site Rare Earth (RE) Catalyst System for Isoprene Polymerization

by Di Kang, Rongqing Ma, Hongfan Hu, Yi Zhou, Guoliang Mao and Shixuan Xin

Polymers 2025, 17(9), 1219; https://doi.org/10.3390/polym17091219 - 29 Apr 2025

Abstract

Bis-(o-dipheylphosphinophenyl)amine, a tridentate (PNP) chelating ligand, and several of their Rare Earth (RE) metal complexes, [bis-(o-dipheylphosphinophenyl)amido]-RER₂, {[(C₆H₅)₂P-o-(C₆H₄)]₂NMR₂ (R = -CH₂- [...] Read more.

Bis-(o-dipheylphosphinophenyl)amine, a tridentate (PNP) chelating ligand, and several of their Rare Earth (RE) metal complexes, [bis-(o-dipheylphosphinophenyl)amido]-RER₂, {[(C₆H₅)₂P-o-(C₆H₄)]₂NMR₂ (R = -CH₂-o-(C₆H₄)NMe₂: M = Y, 1; Nd, 2; Gd, 3;), are prepared in high yields. When activated with the strong Lewis acid MMAO-7, all these complexes exhibit catalytic activity toward the polymerization of isoprene (IP) in non-protic hydrocarbons. While the Nd complex (2) showed moderate activity and stereoselectivity, the Y and Gd complexes (1 and 3) exhibited extremely high catalytic efficiency in IP homo-polymerization, and produced polyisoprene rubber (PI) with 95% to over 99% cis-1,4 stereoselectivity and narrow polydispersity indices (<2.0). Moreover, under industrially relevant conditions, complex 3 can catalyze IP to produce ultrahigh molecular weight PI (UHMW-PI, MW up to 1200–2600 kg/mol) rubber with a very narrow polydispersity index (PDI ca. 1.1–1.6), a high-performance elastomeric material mimic of natural rubber (NR). Full article

(This article belongs to the Section Polymer Chemistry)

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14 pages, 4910 KiB

Open AccessArticle

Enhanced Compression Properties of Open-Cell Foams Reinforced with Shear-Thickening Fluids and Shear-Stiffening Polymers

by Jian Li, Yaoguang Zhou, Mohammad Rauf Sheikhi and Selim Gürgen

Polymers 2025, 17(9), 1218; https://doi.org/10.3390/polym17091218 - 29 Apr 2025

Abstract

Open-cell PU foams have a wide range of industrial applications due to their excellent cushioning, impact protection, packaging, thermal insulation, and sound reduction benefits. The foams absorb impact energy while deforming under compressing and are ideal for applications with severe and repeated loading [...] Read more.

Open-cell PU foams have a wide range of industrial applications due to their excellent cushioning, impact protection, packaging, thermal insulation, and sound reduction benefits. The foams absorb impact energy while deforming under compressing and are ideal for applications with severe and repeated loading conditions. Enhancing and improving their compressive durability is a vital area of ongoing research. We investigated the effect of incorporating shear-stiffening polymers (SSPs) and shear-thickening fluids (STFs) on the compression properties of open-cell foams. Rheological properties of STFs and SSPs prepared for incorporation into the foams confirmed the shear-thickening and shear-stiffening characteristics. Quasi-static compression tests performed at different speeds (6, 60, 120, 180, and 240 mm/s), as well as load-unload compression tests (6 and 24 mm/s), showed that the SSP-filled foam exhibited the most pronounced improvement in the elastic, plateau, and densification regions compared to the neat foam. While the STF-filled foam also improved performance over the neat foam, its advantages over the SSP-filled foam were less pronounced. The performance of the SSP-filled foam improved with increasing compression speeds, while the performance of the STF-filled foam remained relatively stable between 60 and 240 mm/s of load-unload tests. Post-test compression evaluations showed that neat and STF-filled foams quickly regained their original shape, while SSP-filled foams required more time before recovery. This research shows that combining SSP and STF smart materials with open-cell foams substantially improves their compressive performance, especially at high compression rates and load-unloading scenarios, increasing their functional life. Full article

(This article belongs to the Special Issue Mechanical Behaviors and Properties of Polymer Materials, 2nd Edition)

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19 pages, 6264 KiB

Open AccessArticle

Edible Coating Based on Konjac glucomannan Loading Ocimum gratissimum Essential Oil for Postharvest Preservation of Orange

by Xiang Yu, Jingyu Zhu, Jintao Wu, Yuhang Cheng, Ya Gao, Yi Liu and Fatang Jiang

Polymers 2025, 17(9), 1217; https://doi.org/10.3390/polym17091217 - 29 Apr 2025

Abstract

Microbial contamination challenges have led to the development of active edible coatings for fruit preservation. Herein, a Konjac glucomannan (KGM) coating loaded with Ocimum gratissimum (OG) essential oil stabilized by pectin with superior resistance to air permeability, oxidation, and fungal, was prepared in [...] Read more.

Microbial contamination challenges have led to the development of active edible coatings for fruit preservation. Herein, a Konjac glucomannan (KGM) coating loaded with Ocimum gratissimum (OG) essential oil stabilized by pectin with superior resistance to air permeability, oxidation, and fungal, was prepared in situ on the surface of Mandarin oranges to enhance postharvest fruit quality. The results demonstrated that the KGM-pectin-OG (K-P-OG) 1.5 wt% coating exhibited good performance in terms of stability, adhesion, and wetting. Meanwhile, the coating had an ideal air permeability due to its compact and dense structure based on the good compatibility and interactions between the components. The oxygen permeability of the K-P-OG coating was 7.9 × (10⁻¹⁶ g·cm)/(cm²·s·Pa), which was six orders of magnitude lower than that of the KGM coating. The antioxidant, in vitro, and in vivo antifungal activities against Penicillium italicum of the coating were strengthened by the OG emulsion and mainly depended on its concentration. The storage results showed that the K-P-OG 1.5% coating extended the shelf life of Mandarin oranges by 8 days, reduced the weight loss rate by 13%, and increased the firmness and POD during storage by 24.14% and 100%, respectively, compared with the control group. These results demonstrate that K-P-OG can effectively maintain nutrient content and extend the storage time of Mandarin oranges by enhancing antioxidant capacity and inhibiting fruit respiration and microorganism growth. This study presents a strategy for developing edible coatings for postharvest fruit preservation. Full article

(This article belongs to the Section Biobased and Biodegradable Polymers)

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13 pages, 1571 KiB

Open AccessArticle

The Effect of Acidic Immersion Media on the Flexural Properties of a High-Performance Fiber-Reinforced CAD/CAM Technopolymer

by Hanin E. Yeslam, Hazzaa H. Alqahtani, Aws M. Filemban, Sultan O. Jiffri and Abeer K. Tashkandi

Polymers 2025, 17(9), 1216; https://doi.org/10.3390/polym17091216 - 29 Apr 2025

Abstract

Introduction: High-performance fiber-reinforced technopolymers for computer-aided design/computer-aided manufacturing (CAD/CAM) of dental restorations offer superior durability and strength. However, exposure to acidic solutions may adversely affect these mechanical properties. Objective: This study aimed to evaluate the flexural properties of a high-strength commercially available CAD/CAM [...] Read more.

Introduction: High-performance fiber-reinforced technopolymers for computer-aided design/computer-aided manufacturing (CAD/CAM) of dental restorations offer superior durability and strength. However, exposure to acidic solutions may adversely affect these mechanical properties. Objective: This study aimed to evaluate the flexural properties of a high-strength commercially available CAD/CAM fiber-reinforced dental material in response to water, cola, and artificial gastric acid solutions. Method: Forty bar-shaped specimens (1 × 4 × 13 mm) were fabricated from a pre-polymerized glass fiber-reinforced composite (Trilor disks, Bioloren, Saronno, Italy). Ten specimens were randomly selected for baseline testing. The remaining specimens were subdivided into three groups based on the storage media (n = 10): artificial gastric acid solution, Coca-Cola, and deionized water (37 °C, 48 h). Mean flexural strengths and moduli were statistically compared at a significance level of p < 0.05. Results: No statistically significant change in flexural strength was observed after immersion in the different media. However, there was a statistically significant decrease in the flexural modulus after storage for 48 h, regardless of pH. Conclusion: Fiber-reinforced CAD/CAM technopolymers show promising strength stability in response to varying pH conditions. However, further studies are needed to investigate the material’s long-term strength stability. Full article

(This article belongs to the Special Issue Advancements in the Development of Polymer Composites: Design, Fabrication, Properties and Application)

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11 pages, 2584 KiB

Open AccessArticle

Improving Bonding Protocols: The Effect of Selective Dentin Etching with Two Different Universal Adhesives—An In Vitro Study

by Sandro Ferreira, Tiago Rodrigues, Mariana Nunes, Ana Mano Azul, José João Mendes, Ana Filipa Chasqueira and Joana Costa

Polymers 2025, 17(9), 1215; https://doi.org/10.3390/polym17091215 - 29 Apr 2025

Abstract

Universal adhesives can be applied in versatile bonding strategies, with selective dentin etching (SDE) emerging as a promising approach for enhancing dentin–adhesive interfaces. This study evaluated the immediate adhesive interface to dentin of two universal adhesives (Optibond^TM Universal and Futurabond M+) with [...] Read more.

Universal adhesives can be applied in versatile bonding strategies, with selective dentin etching (SDE) emerging as a promising approach for enhancing dentin–adhesive interfaces. This study evaluated the immediate adhesive interface to dentin of two universal adhesives (Optibond^TM Universal and Futurabond M+) with an SDE strategy. Sixty human molars were randomly assigned to six experimental groups (n = 10): control (self-etch strategy), SDE, and SDE3 (SDE with three adhesive layers). After dentin exposure and smear layer simulation, adhesives were applied, followed by composite resin restoration. Microtensile bond strength in 1 mm² beams was performed in a universal testing machine (1 kN; 0.5 mm/min) after 24 h water storage. Failure modes were classified, and the adhesive interfaces were characterized by scanning electronic microscopy. SDE was higher for both adhesives compared to the control group, but was this change statistically significant in Futurabond M+ only (Mann–Whitney, p < 0.001). On the other hand, in Optibond^TM Universal, only SDE3 significantly increased bond strength (Mann–Whitney, p < 0.001). Adhesive failures predominated across all groups. Microscopy images revealed longer and more numerous resin tags in SDE and SDE3 specimens. The SDE strategy enhanced immediate bond strength of these universal adhesives, with product-specific variations, suggesting that application strategies should be tailored to each universal adhesive’s unique formulation to optimize dentin bonding effectiveness. Full article

(This article belongs to the Section Polymer Applications)

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13 pages, 4438 KiB

Open AccessArticle

Reverse Design of High Strength and High Modulus Epoxy Resin Systems Through Computational Modeling with Experimental Validation

by Yilin Tang, Shipeng Zhu, Boya Zhang, Haozhong Lv, Jingshu Wu, Yunhua Yang, Ben Zhang and Jianli Gao

Polymers 2025, 17(9), 1214; https://doi.org/10.3390/polym17091214 - 29 Apr 2025

Abstract

High-strength and high-modulus epoxy resins are key elements for preparing carbon-fiber-reinforced polymer composites, which play an irreplaceable role in aerospace. In this study, five optimal epoxy systems were developed utilizing the reverse design strategy. The reverse design strategy was based on the ideal [...] Read more.

High-strength and high-modulus epoxy resins are key elements for preparing carbon-fiber-reinforced polymer composites, which play an irreplaceable role in aerospace. In this study, five optimal epoxy systems were developed utilizing the reverse design strategy. The reverse design strategy was based on the ideal resin and curing agent structures offered by the AI polymer platform, and the rules were summarized to create an optimum resin formulation. The formulations used m-phenylenediamine (MPD) as the principal curing agent, which was modified with 10 wt% diethyltetramethylenediamine (DETDA), 10 wt% 4,4′-diaminodiphenylmethane (DDM), or 10 wt% triethylenetetramine (TETA) to establish multiple crosslinking networks. Systematic characterization using differential scanning calorimetry (DSC) and rheological analysis revealed that the optimized activation energy was 55.95–63.42 kJ/mol, and the processing viscosity was ≤500 mPa·s at 80 °C. A stepwise curing protocol (3 h@80 °C, 2 h@120 °C, and 3 h@180 °C) was established to achieve a complete crosslinking network. The results showed that the system with 10% DDM had a tensile strength of 132.6 MPa, a modulus of 5.0 GPa, and a glass transition temperature of 253.1 °C. This work advances the rational design of epoxy resins by bridging molecular architecture with macroscopic performance, offering a paradigm for developing a next-generation matrix tailored to accommodate extreme operational demands in high-end engineering sectors. Full article

(This article belongs to the Special Issue Epoxy Polymers and Composites)

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16 pages, 1593 KiB

Open AccessArticle

Clinical Performance of Zirconia Veneers Bonded with MDP-Containing Polymeric Adhesives: A One-Year Randomized Controlled Trial

by Viet Anh Nguyen, Truong Nhu Ngoc Vo, Minh Son Tong, Thi Nhu Trang Nguyen and Thu Tra Nguyen

Polymers 2025, 17(9), 1213; https://doi.org/10.3390/polym17091213 - 29 Apr 2025

Abstract

Acid-etched zirconia has emerged as a high-strength alternative to traditional glass ceramics for laminate veneers in aesthetic dentistry. This randomized, double-blind controlled clinical trial aimed to evaluate the one-year clinical performance of zirconia veneers etched with a hydrofluoric-nitric acid mixture and bonded using [...] Read more.

Acid-etched zirconia has emerged as a high-strength alternative to traditional glass ceramics for laminate veneers in aesthetic dentistry. This randomized, double-blind controlled clinical trial aimed to evaluate the one-year clinical performance of zirconia veneers etched with a hydrofluoric-nitric acid mixture and bonded using a 10-methacryloyloxydecyl dihydrogen phosphate (MDP) containing polymeric adhesive system, compared to lithium disilicate veneers. Fifty-two patients were treated with either translucent zirconia or lithium disilicate veneers, and restorations were bonded using light-cured resin-based adhesives. Clinical parameters, including veneer survival, esthetics, marginal adaptation, postoperative sensitivity, and periodontal health, were assessed using modified United States Public Health Service (USPHS) criteria and periodontal indexes at 2 weeks, 6 months, and 12 months. Both materials showed high survival rates with no statistically significant differences in clinical outcomes. One zirconia veneer debonded early but was successfully rebonded without fracture, while one lithium disilicate veneer fractured upon debonding. The findings support the viability of acid-etched zirconia veneers bonded with polymer-based adhesives as a durable and esthetic restorative option. The study highlights the clinical relevance of polymeric bonding systems in enhancing zirconia veneer performance and reinforces their role in modern adhesive dentistry. Full article

(This article belongs to the Special Issue Polymers & Polymer Composites for Dental Applications)

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31 pages, 7408 KiB

Open AccessReview

Poly(propylene fumarate) Composite Scaffolds for Bone Tissue Engineering: Innovation in Fabrication Techniques and Artificial Intelligence Integration

by Madalina I. Necolau, Mariana Ionita and Andreea M. Pandele

Polymers 2025, 17(9), 1212; https://doi.org/10.3390/polym17091212 - 28 Apr 2025

Abstract

Over the past three decades, the biodegradable polymer known as poly(propylene fumarate) (PPF) has been the subject of numerous research due to its unique properties. Its biocompatibility and controllable mechanical properties have encouraged numerous scientists to manufacture and produce a wide range of [...] Read more.

Over the past three decades, the biodegradable polymer known as poly(propylene fumarate) (PPF) has been the subject of numerous research due to its unique properties. Its biocompatibility and controllable mechanical properties have encouraged numerous scientists to manufacture and produce a wide range of PPF-based materials for biomedical purposes. Additionally, the ability to tailor the degradation rate of the scaffold material to match the rate of new bone tissue formation is particularly relevant in bone tissue engineering, where synchronized degradation and tissue regeneration are critical for effective healing. This review thoroughly summarizes the advancements in different approaches for PPF and PPF-based composite scaffold preparation for bone tissue engineering. Additionally, the challenges faced by each approach, such as biocompatibility, degradation, mechanical features, and crosslinking, were emphasized, and the noteworthy benefits of the most pertinent synthesis strategies were highlighted. Furthermore, the synergistic outcome between tissue engineering and artificial intelligence (AI) was addressed, along with the advantages brought by the implication of machine learning (ML) as well as the revolutionary impact on regenerative medicines. Future advances in bone tissue engineering could be facilitated by the enormous potential for individualized and successful regenerative treatments that arise from the combination of tissue engineering and artificial intelligence. By assessing a patient’s reaction to a certain drug and choosing the best course of action depending on the patient’s genetic and clinical characteristics, AI can also assist in the treatment of illnesses. AI is also used in drug research and discovery, target identification, clinical trial design, and predicting the safety and effectiveness of novel medications. Still, there are ethical issues including data protection and the requirement for reliable data management systems. AI adoption in the healthcare sector is expensive, involving staff and facility investments as well as training healthcare professionals on its application. Full article

(This article belongs to the Special Issue Functional Polymer-Modified Nanocomposites for Tissue Engineering and Biomedical Applications)

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10 pages, 1662 KiB

Open AccessArticle

Chromophore Quench-Labeling for Active Sites Counting in Ti-Based Ziegler–Natta Catalysts

by Antonio Vittoria, Giuseppe Antinucci, Roberta Cipullo and Vincenzo Busico

Polymers 2025, 17(9), 1211; https://doi.org/10.3390/polym17091211 - 28 Apr 2025

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Abstract

Chromophore quench-labeling (CQL) is an elegant and effective method to count the fraction of active metal (x*) in olefin polymerizations mediated by molecular transition metal catalysts. In this study, the method was successfully applied for the first time to a heterogeneous [...] Read more.

Chromophore quench-labeling (CQL) is an elegant and effective method to count the fraction of active metal (x*) in olefin polymerizations mediated by molecular transition metal catalysts. In this study, the method was successfully applied for the first time to a heterogeneous Ti-based Ziegler–Natta catalyst of industrial relevance. CQL experiments using 1-hexene as the monomer ended up with a value of x* = 0.49 ± 0.09%, close to that measured for the same catalyst in the polymerization of propene under otherwise identical conditions using an alternative quenched flow (QF) approach. We ascribe such a low x* value to the fact that the catalytically active species are transient metastable surface Ti adducts, as proposed in the recent literature. Full article

(This article belongs to the Section Polymer Chemistry)

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19 pages, 2384 KiB

Open AccessArticle

Exploring the Relationship Between Stability and Dynamics in Polymer-Based Amorphous Solid Dispersions for Pharmaceutical Applications

by Emeline Dudognon, Jeanne-Annick Bama and Frédéric Affouard

Polymers 2025, 17(9), 1210; https://doi.org/10.3390/polym17091210 (registering DOI) - 28 Apr 2025

Viewed by 22

Abstract

Mixing polymeric excipients with drugs in amorphous solid dispersions (ASD) is known to enhance the bioavailability of drugs by inhibiting their recrystallisation. However, the mechanisms underlying stabilisation remain not fully understood. This study aims to improve our understanding of the role of dynamics, [...] Read more.

Mixing polymeric excipients with drugs in amorphous solid dispersions (ASD) is known to enhance the bioavailability of drugs by inhibiting their recrystallisation. However, the mechanisms underlying stabilisation remain not fully understood. This study aims to improve our understanding of the role of dynamics, particularly the molecular movements that drive instabilities, through investigations of ASD made of Polyvinylpyrrolidone (PVP K12) and a model drug, Terfenadine. The analyses combine temperature modulated differential scanning calorimetry (MDSC) and dielectric relaxation spectroscopy. The results reveal that the produced ASDs are supersaturated with Terfenadine, regardless of the content, and that PVP slows down the dynamics of the blends, limiting the recrystallisation of the drug during heating. Although the ASDs appear homogeneous based on thermal analysis with a single glass transition consistently detected by MDSC, the investigation of the dynamics reveals a dissociation of the main relaxation into two components for PVP contents below 30 wt.%. This dynamic heterogeneity suggests a structural heterogeneity with the coexistence of two amorphous phases of different compositions, each characterised by its own dynamics. The complex evolution of these dynamics under recrystallisation is rationalised by the confrontation with the phase and state diagram of Terfenadine/PVP blends established by MDSC. Full article

(This article belongs to the Topic Broadband Dielectric Spectroscopy Fundamentals and Applications)

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14 pages, 10006 KiB

Open AccessArticle

Surface Modification of Polydopamine Particles with Polyethyleneimine Brushes for Enhanced Stability and Reduced Fragmentation

by Su Hyeon Son, Eun Jin Kim, Hye Young Koo and Won San Choi

Polymers 2025, 17(9), 1209; https://doi.org/10.3390/polym17091209 - 28 Apr 2025

Viewed by 21

Abstract

Polydopamine (Pdop) particles possess unique properties but suffer from inherent instability in aqueous environments due to the gradual release of Pdop fragments. This study demonstrated the successful enhancement of the stability and reduction in fragmentation in Pdop particles through surface engineering strategies. Specifically, [...] Read more.

Polydopamine (Pdop) particles possess unique properties but suffer from inherent instability in aqueous environments due to the gradual release of Pdop fragments. This study demonstrated the successful enhancement of the stability and reduction in fragmentation in Pdop particles through surface engineering strategies. Specifically, we investigated the effects of polyelectrolyte multilayer (PEM) coating and polyelectrolyte (PE) brush grafting. Our results showed that PE brush grafting, particularly with long-chain polyethyleneimine (PEI), was more effective in suppressing Pdop fragment release compared to PEM coating. The L-PEI grafted Pdop particles (2.28 chains/nm²) exhibited remarkable stability across a wide pH range (3–9), with inhibition rates exceeding 90% in most cases, reaching 93% at pH 5. Furthermore, a direct correlation between PEI grafting density (0.64 to 2.28 chains/nm²) and inhibition rate was observed, with higher densities yielding greater stability. These findings offer a promising approach for stabilizing Pdop particles for diverse applications. Full article

(This article belongs to the Section Polymer Processing and Engineering)

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24 pages, 3118 KiB

Open AccessArticle

Sago-Starch-Derived Sodium Starch Glycolate: An Effective Superdisintegrant to Enhance Formulation Performance

by Okta Nama Putra, Ida Musfiroh, Derina Paramitasari, Karjawan Pudjianto, Emmy Hainida Khairul Ikram, Chaidir Chaidir and Muchtaridi Muchtaridi

Polymers 2025, 17(9), 1208; https://doi.org/10.3390/polym17091208 - 28 Apr 2025

Viewed by 117

Abstract

This study focused on optimizing sago-starch-derived sodium starch glycolate (SSG) as a superdisintegrant using a Response Surface Methodology (RSM). The aim was to enhance the formulation performance by achieving an optimal degree of substitution (DS) in the synthesis of SSG from sago starch [...] Read more.

This study focused on optimizing sago-starch-derived sodium starch glycolate (SSG) as a superdisintegrant using a Response Surface Methodology (RSM). The aim was to enhance the formulation performance by achieving an optimal degree of substitution (DS) in the synthesis of SSG from sago starch and evaluating its performance in mefenamic acid tablet formulation. The SSG was synthesized using an organic solvent slurry method, which involves crosslinking starch with sodium trimetaphosphate (STMP) and substituting it with sodium monochloroacetate (SMCA). The reaction conditions, including the temperature, SMCA ratio, and reaction time, were optimized using the RSM. The optimal conditions were identified as a temperature range of 45–55 °C, an SMCA ratio of 0.75–1.5, and a reaction time of 120–240 min. The maximum predicted DS value was 0.24, with a validated DS value of 0.246 ± 0.021. The SSG-containing mefenamic acid formulation met USP standards and showed a superior disintegration time compared to the existing SSG. The optimized SSG derived from sago starch can be effectively used as a superdisintegrant in pharmaceutical formulations, offering a sustainable and economically viable alternative source of SSG. This contributes to the development of more effective drug delivery systems and promotes sustainable agriculture in Indonesia. Full article

(This article belongs to the Special Issue Advanced Polymer Materials: Synthesis, Structure, and Properties)

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14 pages, 3971 KiB

Open AccessArticle

Effect of Annealing on the Mechanical Properties of Composites of PLA Mixed with Mg and with HA

by Carmen Sánchez González, Aurora Pérez Jiménez, Mauro Malvé and Cristina Díaz Jiménez

Polymers 2025, 17(9), 1207; https://doi.org/10.3390/polym17091207 - 28 Apr 2025

Viewed by 111

Abstract

Polylactic acid (PLA) is a bioresorbable and biocompatible material and is a promising alternative to the current materials used for permanent implants as it has osteosynthesis properties. However, this material has some drawbacks due to its low mechanical and thermal resistance after 3D [...] Read more.

Polylactic acid (PLA) is a bioresorbable and biocompatible material and is a promising alternative to the current materials used for permanent implants as it has osteosynthesis properties. However, this material has some drawbacks due to its low mechanical and thermal resistance after 3D printing. Extensive research has been conducted to improve the properties of this material, for example, with the addition of other compounds, such as magnesium (Mg) or Hydroxyapatite (HA). These reinforced materials have been shown to reduce the internal stress of the matrix of PLA, improving the thermal, optical and structural properties of the material, even though the performance achieved is lower than needed to be implanted. In addition, although it is known that the addition of Mg or HA affects the mechanical performance of the material, mechanical properties have not been studied in the literature. Thus, the aim of this study is to research the effect of thermal post-processing based on annealing of composites made of PLA with Mg and PLA with HA, manufactured by fused filament fabrication, with the goal of finding an improvement in the mechanical properties of these materials. As a result, different designs of annealing processes have been studied with different reinforced materials and their mechanical properties have been compared, studying axial traction and compression, radial compression as well as flexibility, among others. The comparative results achieved show the relevance of the design of the annealing process for the improvement of the mechanical properties of these materials. Full article

(This article belongs to the Special Issue Polymer/Ceramic Composites, 2nd Edition)

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21 pages, 4834 KiB

Open AccessArticle

A Multifunctional PEEK Composite Scaffold with Immunomodulatory, Angiogenic, and Osteogenic Properties for Enhanced Bone Regeneration

by Mengen Zhao, Han Yang, Qianwen Yang, Chao Zhang, Jie Liu, Zhaoying Wu, Lijun Wang, Wei Zhang, Bing Wang and Wenliang Liu

Polymers 2025, 17(9), 1206; https://doi.org/10.3390/polym17091206 - 28 Apr 2025

Viewed by 47

Abstract

Polyetheretherketone (PEEK) is a widely used material in bone tissue engineering due to its favorable mechanical properties and radiolucency. However, its bioinert nature and lack of osteogenic activity restrict its ability to support effective bone regeneration. In this study, a novel APS-coated plasma-treated [...] Read more.

Polyetheretherketone (PEEK) is a widely used material in bone tissue engineering due to its favorable mechanical properties and radiolucency. However, its bioinert nature and lack of osteogenic activity restrict its ability to support effective bone regeneration. In this study, a novel APS-coated plasma-treated sulfonated bioactive PEEK scaffold (APS/PSBPK) was developed to overcome these limitations. The scaffold integrates strontium-doped bioactive glass (SrBG) to enhance biocompatibility and osteogenic potential, while astragalus polysaccharide (APS) was incorporated via plasma cleaning to modulate immune responses and promote vascularization. In vitro studies demonstrated that the APS/PSBPK scaffold facilitates M2 macrophage polarization, reduces pro-inflammatory cytokines, and enhances the secretion of anti-inflammatory factors. It also promotes endothelial cell migration and angiogenesis while supporting the adhesion, proliferation, and osteogenic differentiation of rBMSCs. In vivo experiments revealed that the scaffold effectively regulates the immune microenvironment, promotes vascularization, and accelerates bone regeneration. Thus, the APS/PSBPK composite scaffold serves as a multifunctional biomaterial with significant potential for applications in bone repair and regeneration by combining immunomodulation, angiogenesis, and osteogenesis. Full article

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18 pages, 4106 KiB

Open AccessArticle

Cellulose Nanocrystal and Polymer Composite Microspheres for Methylene Blue Adsorption

by Yaxuan Deng, Zenghui Li, Rui Wang and Yue Shi

Polymers 2025, 17(9), 1205; https://doi.org/10.3390/polym17091205 - 28 Apr 2025

Viewed by 125

Abstract

In the present study, cellulose composite microspheres were synthesized based on the reversed-phase suspension method by introducing cellulose nanocrystals (CNCs) into polyacrylamide (PAM), followed by partial hydrolysis. Their adsorption performance for methylene blue (MB) dye in aqueous solution was investigated by varying the [...] Read more.

In the present study, cellulose composite microspheres were synthesized based on the reversed-phase suspension method by introducing cellulose nanocrystals (CNCs) into polyacrylamide (PAM), followed by partial hydrolysis. Their adsorption performance for methylene blue (MB) dye in aqueous solution was investigated by varying the CNC content, pH value, and particle size of the microspheres, showing excellent removal efficiency and a good regeneration performance. In addition, the adsorption kinetics were determined in accordance with the quasi-secondary kinetic model, and the equilibrium isotherm performance followed the Langmuir adsorption model. This work provides a reliable experimental basis and solid theoretical foundation for the potential application of cellulose-based composite microspheres in the field of wastewater treatment. They are expected to represent a highly efficient adsorbent material and promote the development of related fields. Full article

(This article belongs to the Section Polymer Composites and Nanocomposites)

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18 pages, 2100 KiB

Open AccessArticle

Polyether- and Tertiary Amine-Modified Silicone Surfactants: Synthesis and Surface Performance Across pH Ranges

by Yi Guo and Cheng Yao

Polymers 2025, 17(9), 1204; https://doi.org/10.3390/polym17091204 - 28 Apr 2025

Viewed by 120

Abstract

In this study, polymerized silicone surfactants were modified with polyether and tertiary amine groups with the aim of improving the surface performance. Various PSiEO/(PO)-OH(CH₃) surfactants were synthesized and their structures and performance were characterized through ¹H NMR, FTIR spectroscopy, static [...] Read more.

In this study, polymerized silicone surfactants were modified with polyether and tertiary amine groups with the aim of improving the surface performance. Various PSiEO/(PO)-OH(CH₃) surfactants were synthesized and their structures and performance were characterized through ¹H NMR, FTIR spectroscopy, static surface tension, dynamic surface tension, zeta potential, and dynamic light scattering measurements. Subsequently, the modified silicones were incorporated as surfactants in aqueous solutions with different pH values. The surfactants with different hydrophobic/hydrophilic groups and end-capping groups exhibited different surface performances over a wide pH range. Thermodynamic parameters indicated that the micellization and adsorption of these surfactants were endothermic and spontaneous processes driven by entropy. The processes were hindered by increasing the solution pH and modification with hydrophobic groups. The aggregation behavior was significantly different under acidic, neutral, and basic aqueous conditions. Full article

(This article belongs to the Section Polymer Applications)

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12 pages, 9536 KiB

Open AccessArticle

A Silane Cross-Linked Cellulose-Based Separator for Long-Life Lithium Metal Batteries Application

by Jinghao Cui, Hongliang Meng and Wei Li

Polymers 2025, 17(9), 1203; https://doi.org/10.3390/polym17091203 - 28 Apr 2025

Viewed by 112

Abstract

Cellulose-based separators with good electrolyte wettability and thermal stability have attracted extensive attention in the area of lithium metal battery (LMB) applications. However, their low mechanical strength in an electrolyte has seriously hindered their cycling performance of assembled LMB. Herein, a silane-crosslinked propionylated [...] Read more.

Cellulose-based separators with good electrolyte wettability and thermal stability have attracted extensive attention in the area of lithium metal battery (LMB) applications. However, their low mechanical strength in an electrolyte has seriously hindered their cycling performance of assembled LMB. Herein, a silane-crosslinked propionylated cellulose-based separator (PBF-GPTMS) was prepared. The resulting separator exhibited high wet strength (18.7 MPa) and electrolyte uptake (312 wt%). Molecular simulation revealed that Young’s modulus of the silanized propionylated cellulose model was 14.64 GPa under EC/DMC/DEC conditions, which was higher than that of the propionylated cellulose model (6.89 GPa). In particular, the XPS spectra of the Li foil in the PBF-GPTMS-assembled battery after cycling suggested a lower amount of HF formed during cycling. Accordingly, the assembled Li/Separator/LiFePO₄ cell showed excellent cycle performance with capacity retention of 94.5% after 300 cycles at 0.5 C and 93.6% after 160 cycles at 1 C, respectively. This idea would provide novel insights into the design of bio-based separators for long-life LMBs. Full article

(This article belongs to the Special Issue Latest Technological Advancements in Polymers Used for Lithium-Ion Battery Applications)

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31 pages, 8799 KiB

Open AccessArticle

Correlation Between Conditions of Polyaniline Interlayer Formation and the Structure and Performance of Thin-Film Composite Membranes for Nanofiltration Prepared via Interfacial Polymerization

by Katsiaryna S. Burts, Tatiana V. Plisko, Anastasia V. Penkova, Bingbing Yuan, Sergey S. Ermakov and Alexandr V. Bildyukevich

Polymers 2025, 17(9), 1199; https://doi.org/10.3390/polym17091199 - 28 Apr 2025

Viewed by 178

Abstract

Correlations between conditions of the polyaniline (PANI) interlayer formation on the surface of a polysulfone (PSF) porous membrane substrate and the structure and performance of thin-film composite (TFC) membranes for nanofiltration with a polyamide (PA) selective layer prepared via interfacial polymerization (IP) were [...] Read more.

Correlations between conditions of the polyaniline (PANI) interlayer formation on the surface of a polysulfone (PSF) porous membrane substrate and the structure and performance of thin-film composite (TFC) membranes for nanofiltration with a polyamide (PA) selective layer prepared via interfacial polymerization (IP) were studied. It was shown that application of the PANI layer significantly enhanced hydrophilicity (the water contact angle decreased from 55 ± 2° down to 26–49 ± 2°), decreased pore size and porosity, and increased the surface roughness of the selective layer surface of porous PSF/PANI membrane substrates due to the formation of bigger PANI globules, which affect the formation of the PA layer of TFC membranes via IP. It was shown that the application of the PANI intermediate layer yielded the formation of a thinner PA selective layer, a decline in surface roughness, and an increase in hydrophilicity (the water contact angle declined from 28 to <10°) and crosslinking degree of the selective layer of TFC NF membranes. The developed approach allows us to enhance the water permeation up to 45–64 L·m⁻²·h⁻¹ at ΔP = 0.5 MPa and improve membrane selectivity (rejection coefficient of MgSO₄—>99.99%; LiCl—5–25%; sulfadimetoxine—80–95%) and also ensure enhanced long-term operational stability of TFC nanofiltration membranes with a PANI interlayer. Moreover, Mg²⁺/Li⁺ separation factor values were found to increase to 37 and 58 for PANI-modified membranes compared to 9 and 8 for the reference NF-PSF membranes. Full article

(This article belongs to the Special Issue Recent Trends in Polymer Membranes: Fabrication Technique, Characterization, Functionalization, and Applications in Environmental Science, 2nd Edition)

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18 pages, 3964 KiB

Open AccessArticle

The Thermal and Mechanical Performance of Leather Waste-Filled Bio-Based Thermoplastic Polyurethane Composites

by Sara Naderizadeh, Anna Faggionato, Muhammad Umar Nazir, Rosario Mascolo, Mohammad Mahbubul Hassan, Emiliano Bilotti and James J. C. Busfield

Polymers 2025, 17(9), 1202; https://doi.org/10.3390/polym17091202 - 27 Apr 2025

Viewed by 118

Abstract

The leather tanning industry generates a substantial quantity of solid waste, which, in part, is discarded in the environment in landfills or incinerated. One alternative end-of-life solution is to manufacture engineered materials by forming composites with a thermoplastic polymer/binder. In this work, leather [...] Read more.

The leather tanning industry generates a substantial quantity of solid waste, which, in part, is discarded in the environment in landfills or incinerated. One alternative end-of-life solution is to manufacture engineered materials by forming composites with a thermoplastic polymer/binder. In this work, leather fibres (LFs) were melt-compounded into partially bio-based thermoplastic polyurethane (TPU), at leather fibre contents between 10 and 30% (TPU/LF), followed by compression moulding or 3D printing. The results showed that the incorporation of LF into the polymer matrix produced materials with a Young’s modulus comparable to that of leather. The melt extrusion processing influenced the polymer chain orientation and the resulting mechanical performance. The cyclic stress softening and abrasion resistance of the TPU/LF materials were evaluated to understand the potential of this material to be used in the footwear industry. The level of LF incorporation could be tailored to produce the specific targeted mechanical properties. This work demonstrates that LF could be used to produce materials with a high potential to be used in the fashion industry. Full article

(This article belongs to the Special Issue Sustainable Development of Advanced Polymer Composites)

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16 pages, 3199 KiB

Open AccessArticle

Thin-Layer Drying Model and Antifungal Properties of Rubber Sheets Produced with Wood Vinegar as a Substitute for Formic and Acetic Acids

by Wassachol Wattana, Putipong Lakachaiworakun, Natworapol Rachsiriwatcharabul, Visit Eakvanich, Panya Dangwilailux and Wachara Kalasee

Polymers 2025, 17(9), 1201; https://doi.org/10.3390/polym17091201 - 27 Apr 2025

Viewed by 111

Abstract

Currently, workers in the ribbed smoked sheet (RSS) rubber production industry face increasing health risks, primarily due to their direct involvement in converting fresh latex into raw rubber sheets. This process involves the manual addition of appropriately diluted commercial formic acid and acetic [...] Read more.

Currently, workers in the ribbed smoked sheet (RSS) rubber production industry face increasing health risks, primarily due to their direct involvement in converting fresh latex into raw rubber sheets. This process involves the manual addition of appropriately diluted commercial formic acid and acetic acid to induce coagulation, resulting in a tofu-like consistency, which is subsequently processed into rubber sheets. Previous studies have indicated that the use of commercial formic and acetic acids poses significant health hazards to workers and contributes to environmental pollution. Therefore, this study explores the feasibility of replacing commercial formic and acetic acids with wood vinegar derived from para-rubber wood, bamboo, and eucalyptus in the RSS production process. Wood vinegar samples from the three biomass sources were analyzed for their organic compound compositions using gas chromatography and subsequently used as coagulants in the preparation of raw rubber sheets. The drying kinetics and antifungal properties of the resulting sheets were then evaluated. The results revealed that wood vinegar derived from para-rubber wood contained the highest concentration of acetic acid (41.34%), followed by bamboo (38.19%) and eucalyptus (31.25%). Rubber sheets coagulated with wood vinegar from para-rubber wood and bamboo exhibited drying kinetics comparable to those obtained using acetic acid, with the two-term exponential model providing the best fit. Conversely, rubber sheets coagulated with eucalyptus-derived wood vinegar, which had a relatively high concentration of phenolic derivatives (22.08%), followed drying behavior consistent with the Midilli et al. model, similar to sheets treated with formic acid. In terms of antifungal properties, five fungal genera—Aspergillus, Penicillium, Fusarium, Trichoderma, and Paecilomyces—were identified on the rubber sheets. Fungal growth was most pronounced in the control samples (untreated with wood vinegar), whereas samples treated with wood vinegar exhibited significantly reduced fungal colonization. These findings indicate that wood vinegar is effective in inhibiting fungal growth on the surface of rubber sheets and may serve as a safer and more environmentally friendly alternative to commercial acid coagulants. Full article

(This article belongs to the Section Polymer Networks and Gels)

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19 pages, 2246 KiB

Open AccessArticle

Ammonium-Containing Methacrylic Polymer Brushes with Adjustable Hydrophilicity: Synthesis and Properties in Aqueous Solutions

by Denis Kamorin, Alexander Simagin, Oleg Kazantsev, Maria Savinova, Maria Simonova, Denis Sadkov, Ildar Arifullin and Yaroslav Dolinov

Polymers 2025, 17(9), 1200; https://doi.org/10.3390/polym17091200 - 27 Apr 2025

Viewed by 67

Abstract

Reversible addition–fragmentation chain-transfer (RAFT) polymerization was used to synthesize novel thermoresponsive cationic molecular brushes with high yields—namely of copolymers of methoxyoligo(ethylene glycol) methacrylate, alkoxyoligo(ethylene glycol) methacrylate, and N-methacryloylaminopropyl-N,N-dimethyl-N-propylammonium bromide. Controlled polymerization yielded polymers with a molecular weight dispersity of ≤1.3 and conversions exceeding [...] Read more.

Reversible addition–fragmentation chain-transfer (RAFT) polymerization was used to synthesize novel thermoresponsive cationic molecular brushes with high yields—namely of copolymers of methoxyoligo(ethylene glycol) methacrylate, alkoxyoligo(ethylene glycol) methacrylate, and N-methacryloylaminopropyl-N,N-dimethyl-N-propylammonium bromide. Controlled polymerization yielded polymers with a molecular weight dispersity of ≤1.3 and conversions exceeding 80%. The influence of the cationic molecular brushes’ composition on their solubility in water and organic solvents, interfacial tension at the water–oil interface, and aggregation behavior in aqueous solutions was investigated. For the first time, we report the design of thermoresponsive cationic molecular brushes combining an antibacterial potential and tunable hydrophilic–hydrophobic properties, enabling highly precise control over their LCST behavior (17–68 °C) through composition tuning. The solubilization capacity of the hydrophobic compounds of brush micelles in water increased with the hydrophobic comonomer content. These polymers exhibited interfacial activity, significantly reducing the water–oil interfacial tension, with critical micelle concentrations (CMCs) of 3–10 mg/L. It was shown that the amphiphilic properties of the copolymers in aqueous solutions can be easily tuned in a desired direction by varying the content of the comonomer units. The obtained data indicate the potential of the polymers as micellar nanocarriers for controlled drug delivery. Full article

(This article belongs to the Section Polymer Chemistry)

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15 pages, 13259 KiB

Open AccessArticle

N- and O- Doped Porous Carbon Nanosheets Prepared from Templating Methodology for Supercapacitors

by Baoning Zhu, Jinghua Liu, Qijun Zhong, Yaru Wen, Qianqian Dong, Yuhao Li, Qianqian Jin and Yao Lu

Polymers 2025, 17(9), 1198; https://doi.org/10.3390/polym17091198 - 27 Apr 2025

Viewed by 107

Abstract

Heteroatom-doped biomass-derived porous carbon materials show promising applications as electrode components in energy storage technologies. In this investigation, we present a template-assisted pyrolysis procedure to fabricate nitrogen–oxygen dual-doped carbon materials. Firstly, the precursor and template initially polymerized to form a white jelly-like gel, [...] Read more.

Heteroatom-doped biomass-derived porous carbon materials show promising applications as electrode components in energy storage technologies. In this investigation, we present a template-assisted pyrolysis procedure to fabricate nitrogen–oxygen dual-doped carbon materials. Firstly, the precursor and template initially polymerized to form a white jelly-like gel, which was freeze-dried to create a nanosheet-assembled structure. Subsequent high-temperature pyrolysis induced the formation of a porous structure with nanosheet morphology. The CMC-ZnK sample derived from the dual template of potassium citrate and zinc acetate pyrolyzed at 800 °C exhibits optimal electrochemical performance, delivering a specific capacitance of 271.4 F g⁻¹ at 1 A g⁻¹ in a three-electrode configuration, along with outstanding rate capability (90% retention, 244 F g⁻¹ at 10 A g⁻¹). The constructed supercapacitor demonstrated an energy density of 6.5 Wh kg⁻¹ under a power density of 500 W kg⁻¹. Furthermore, this study systematically investigated the performance variation mechanisms at different temperatures, revealing the relationship between structural composition and temperature in biomass materials. Full article

(This article belongs to the Section Polymer Applications)

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34 pages, 5681 KiB

Open AccessArticle

Study of Mathematical Models Describing the Thermal Decomposition of Polymers Using Numerical Methods

by Gaziza M. Zhumanazarova, Akmaral Zh. Sarsenbekova, Lyazzat K. Abulyaissova, Irina V. Figurinene, Rymgul K. Zhaslan, Almagul S. Makhmutova, Raissa K. Sotchenko, Gulzat M. Aikynbayeva and Jakub Hranicek

Polymers 2025, 17(9), 1197; https://doi.org/10.3390/polym17091197 - 27 Apr 2025

Viewed by 86

Abstract

This research presents the results of a combined numerical and experimental study of the thermal decomposition behavior of copolymers based on polypropylene glycol fumarate phthalate. The thermal decomposition of polymers plays a key role in various fields, such as waste recycling and energy [...] Read more.

This research presents the results of a combined numerical and experimental study of the thermal decomposition behavior of copolymers based on polypropylene glycol fumarate phthalate. The thermal decomposition of polymers plays a key role in various fields, such as waste recycling and energy recovery, and in the development of new materials. The objective of this study is to model the degradation kinetics using thermogravimetric data, matrix-based numerical methods, and quantum chemical calculations. To solve the resulting systems of linear algebraic equations (SLAEs), matrix decomposition algorithms (QR, SVD, and Cholesky) were employed, which enabled the determination of activation energy values for the process. Comparison of the activation energy (E_a) results obtained using the decomposition method of Cholesky (207.21 kJ/mol), normal equations (205.22 kJ/mol), singular value decomposition (206.23 kJ/mol), and QR decomposition (206.23 kJ/mol) showed minor changes that were associated with the features of each method. Quantum chemical calculations based on density functional theory (DFT) at the B3LYP/6-31G(d) level were performed to analyze the molecular structure and interpret the IR spectra. This study establishes that the content of functional groups (ether and ester) and the type of chemical bonds exert critical influences on the decomposition mechanism and associated thermal parameters. The results confirm that the polymer’s structural architecture governs its thermal stability. The scientific novelty of this work lies in the integration of numerical approximation methods and quantum chemical analysis for investigating the thermal behavior of polymers. This approach is applied for the first time to copolymers of this composition and may be employed in the design of heat-resistant materials for agricultural and environmental applications. Full article

(This article belongs to the Section Polymer Chemistry)

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25 pages, 2008 KiB

Open AccessReview

Recent Advances in the Applications and Studies of Polysaccharide-, Protein-, and Lipid-Based Delivery Systems in Enhancing the Bioavailability of Capsaicin—A Review

by Xiang Qiu, Jing Xie and Jun Mei

Polymers 2025, 17(9), 1196; https://doi.org/10.3390/polym17091196 - 27 Apr 2025

Viewed by 169

Abstract

The primary active ingredient in capsicum is capsaicin. However, capsaicin bioavailability is low due to its restricted water solubility, and its potent spicy flavor will further restrict its use in food. This paper provides a complete overview of capsaicin. The biological activity of [...] Read more.

The primary active ingredient in capsicum is capsaicin. However, capsaicin bioavailability is low due to its restricted water solubility, and its potent spicy flavor will further restrict its use in food. This paper provides a complete overview of capsaicin. The biological activity of capsaicin and its impacts on metabolism in vivo are described. To increase capsaicin stability and bioavailability, several capsaicin-based delivery systems, including liposomes, double emulsions, nanoparticle mesosystems, and multiple systems made of distinct hydrocolloids, are covered in this review. Finally, potential uses for food preservation are introduced in line with this. Numerous delivery systems introduced in this review have effectively solved the problems of poor water solubility and poor bioavailability of capsaicin. Although capsaicin has potential uses in food preservation, there is little research on its application in functional food development. More innovative capsaicin-based delivery methods should be established, and more capsaicin-based applications should be developed in the future. Full article

(This article belongs to the Special Issue Biopolymeric Hydrolysates and Functional Polymers: Innovations in Food Applications and Shelf-Life Enhancement)

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Polymers, Volume 17, Issue 9 (May-1 2025) – 97 articles

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